Current technology allows a portion of a song, movie, or other unknown content items to be identified by comparing it against a database of known content. To facilitate identification of the unknown content, it is known to generate fingerprints of both the known and unknown content items, and compare the fingerprints. These fingerprints can include audio watermarks. In cases where fingerprints are used, the database of known content is sometimes used to store fingerprints of distinct content items.
In some instances, the database storing the fingerprints of the known content is also used to store timestamps, indicating particular times at which particular items of known content were broadcast. The unknown content can also include timestamps, and by performing a two-step comparison that matches both the fingerprints and the timestamps of unknown distinct content items with the fingerprints and timestamps stored in the database of known content items, information can be deduced about a source of the unknown content item.
Currently available technology, however, requires having a comprehensive database of known content items to be compared against each unknown content item, because if an unknown content item is not included in the database of known content items, any attempt to identify the unknown content item will be unsuccessful.
Even when attempting to identify broadcast content using a fingerprint of a known media item included in the comprehensive database, it can be difficult to identify subtle changes in a broadcast content item. For example, if a fingerprint comparison is made between a media item actually broadcast and a known media item, but the media item actually broadcast has been subtly altered, the actually-broadcast media item may not be identified as a match because of the changes. For these and other reasons, currently available technology is less than ideal.